One vertex per element, one color per generator, with an edge from x to x·s.
(2,5)(6,8)(9,10)(11,17)(12,13)(14,22)(15,16)(18,23)(19,20)(21,24)(26,31)(28,34)(29,37)(35,39) involution — undirected(3,7)(6,8)(10,16)(12,17)(18,22)(20,24)(26,31)(27,33)(32,38)(35,39) involution — undirected(1,2)(3,6)(4,5)(7,8)(9,11,15,13)(10,12,16,17)(14,19,23,21)(18,20,22,24)(25,26,30,31)(27,34,33,28)(29,32,37,38)(35,40,39,36)(1,3)(2,6)(4,7)(5,8)(9,12)(10,11)(13,16)(14,20)(15,17)(18,19)(21,22)(23,24)(25,27,30,33)(26,28,31,34)(29,35,37,39)(32,36,38,40)(1,2)(3,6)(4,5)(7,8)(9,13,15,11)(10,17,16,12)(14,21,23,19)(18,24,22,20)(25,28)(26,27)(29,36)(30,34)(31,33)(32,35)(37,40)(38,39)(9,14,15,23)(10,18,16,22)(11,19,13,21)(12,20,17,24)(25,29)(26,32)(27,35)(28,36)(30,37)(31,38)(33,39)(34,40)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.